Recombination experiments on the odontogenic roles of mouse dental papilla and dental sac tissues in ocular grafts

Abstract

First molar tooth germs were dissected from mandibles of mouse embryos 16, 17, 18 and 19 days of gestational age. The tooth rudiments were separated into dental papilla, dental sac and enamel organ after enzymic digestion. These embryonic dental tissues were recombined and grown for 4 weeks in anterior chambers of eyes of homologous adult mice. The removal of the dental sac from recombinations of only dental papillae and enamel organs did not significantly alter the proportion of grafts which formed teeth when compared with those grafts which consisted of all 3 dental tissues. Both groups of recombinants formed teeth in 50–80 per cent of the grafts cultured. The dental papilla and dental sac tissues showed the same inductive activity with the enamel organ with the 16-day-old tissues. However, the dental papilla cells maintained their inductive capacity for a longer period. Whereas 70 per cent of the 16-day-old tissue recombinations of dental sac and enamel organ formed teeth, only 15 per cent of the recombinations of older ages of the same tissues formed teeth.